Hmm, I think plenty of administrations (or rather, legislative bodies, if we actually want to get back to the Constitution) have acted in a way that made it less profitable for businesses to operate, so I think it's very possible to close.
Cryptocurrency regulation isn't a cause that most people are passionate about in either direction, so reeling it back in won't afford politicians any popular support. All it can do is create rich enemies who spend lots of money to attack political threats. There's simply no incentive to crack down on it.
